Filter



June 16, 1942. J. M. CHALMERS FILTER Filed Oct. 21, 1959 INVE1VTOR JamesM Cha/mens A T TORNE Y Patentd June '16, 1942 UNITED STATES ,PATENTOFFICE T James M. Chalmers, East ran e, N. J., assignor to Oliver UnitedFilters Incorporated, Oakland,

Calif., -a corporat0nof Nevada Application October 21, 1939; Serial No.300,596 2blaims. (Cl.210186) This invention relates to filters forsepara;ting solids from liquids and particularly to that type of filterwherein the filter medium per se consists of a layer or precoat ofcomminutedimaterial such as diatomaceous earth and wherein the outersurface of such precoat is continuously or priodically shaved ofl' so ascontinuously to present a fresh filtering surface to the material beingfiltered.

In general, the object of the inventioh is the provision of a filterhaving a conical precoated filtering surface and a conical cuttercoaxially disposed with said surface and arranged for longitudinal axialmovement so that the blades of the cutter may be advanced toward orretracted features, some of which with the foregoing will be set forthat length in the following description where that form of the inventionwhich has been selected for illustration in the drawing accompanying andforming a part of the present specification is outlined in full. In saiddrawing, one form of the invention is shown, but it is to be understoodthat it is not limited to such form, since the invention as set forth inthe claims may be embodied in a plurality of forms.

Referrng to the drawing: A Figure*1 is a ver. ical mid-section of aprecoat filter embodying the objects of my invention.

Figure 2 is a partial top plan view of the filter shown in Figure 1.

Figure, 3 ls n..enlarged vertical section of the upper end of themechanism shown in Figure 1.

Figure 4 is a section taken on the line tl-l of Figure. 1.4

The fil er shown in these figures comprises a cylindrical casing lprovided with a feed inlet 2, a filtrate outlet 3, a relief outlet 5,and a drain nular flange l5 seats against and is bolted to an inwardlyextending annular flange ll formed integral with the casing l. The innersurfaces of the rings l3 and |4 are formed with annlar grooves l8 and l9which aid in holding a conical layer or precoat 20 of filtering materialsuch as diatomacecus earth to the perforated basket l2. The rings I3 andHI are. held in fixed position by vertical circumferentially spaced ribs2|. By having available several perforated baskets, it is possible toreadily replace them by simply removing the conical sump li andunbolting the lower annular flange 15 of the basket from the.

annular flange I1 of the casing I.

Carried on brackets supported on the circular angle 26 welded to thed0me 6 of the cas-v ing I is a split gear housing 21. Journaled inspaced bearings 28 and 25 formed -in the gear housing 21 is a shaft 3|,and keyed to this shaft within the housing are a pnion 32 and a wormwheel 33. The worm wheel 33 is adapted to be driven by a worm 34 formedon a shaft 35 extending through the gear casing 21 and arranged to bedriven by any suitable source of power.

Extending through.the stufing box 'l and j'ournaled in bearngs 35 and 31formed in the gear housing 21 is a hollow shaft 38. Kcycd to this shaftwithin the gear housing is a gear wheel 39 arranged to mesh with and bedriven by the pinion 32.

Extending upwardly from the gear casing 21 is a frame M' formed with alaterally extending bracket 42. The bracket 42 carries a bearing Q3through which the upper end of the shaft 3i extends, and keyed to theupper end of the shaft is a lever 45 formed with an overhanging bracket36. Suspended from a bearing 4'l formed at the end of the bracket 46 isa pin 48, the lower end of outlet E. The upper end of the cylindricalcasing l is 'closed by a dome-shaped top S formed with a stung box i,and the lower end of the casing i terminates in a. fiange 8 to which isbolted the fiange 9 of a conical sump ii. Dispcsed Within the casing lis a conical perforated basket l2 secured at its upper end to a taperedring l3 and at its lower end to a ring It provided with an outwardlyflange I5. The tapcred cuter surface of the ring l3 seats against atapered flange IS welded to the inner surface of the casing i. and theanextendng annular' which is joumaled in a bearing 49 formed at theinner end of the lever 45. Keyed to the pin 58 are a plurality of gearwheels 5l of varyingdiameters, and a driven sprocket wheel 52 adapted tobe driven by the sprocket wheel 45 through a chain 53. The leverterminates at its left end in a handle 54, and is formed with an arouateslot 55 through which extends a screw 56 carried by the bracket 42. Thelever 45 may therefore be secured within limits in any desired positionwith relation to the bracket 42 by a wing riut 51 threaded to the screw56.

arranged to be placed in mesh with any one of thegear.wheels 5| keyed tthepin 48. To accompllsh this 'purpose the hub of the-"gear 64 isprovided with a='recess 85 for the accommodation of a ball66,a-spring6l, anda nut 68, and

the upper end of the shaft 62 is-formed with a plurality of spacedball-receiving recesses 59. The spacing of these recesses 69 is made toconform with the spacing of the gears so that the gear 64 may be keyedto the shaft 82 in such a way as to mesh with any one of the desiredgears 5l.' To change the gear ratio between the shafts 3| and 62, thelever 45 is flrst rotated so as to bring the gears 5| free.and clear ofthe gear64,

the gear 64 is then adjusted longitudinally on the shaft 62 so as tomesh with the desired gear Si, and this having been done the selectedgear 5! is brought into mesh with the gear 64. by rotating the lever 45and looking it in place.

y Secured to the lower end of the hollow shatt 38 within the casing l isa spider ll formed with tapered radial fianges i2.' Secured to theradial flanges '32 are cutters or blades E3 arranged to describe duringtheir rotation a:conical surface in coni0rmity with the conical surfaceof the precoat 20 carried by the perforated basket l2. The rate ofrotation of the hollow shaft 3.8

and therefore of the cutters E3 depends upon the gear ratio between thepinion 32 and the gear 39. The movement of the shaft 38 along its ownaxis, howev*=r. depends upon the relative rotation between the hollowshaft 38 and the shaft 62, and in this connection it should be notedthat both,oi these members are positively'driven. The movement of theshaft 38 along its own axis may therefore be varied by selectivelyengaging the ring gear 543 with any one of the gears Si without in anyway changing the rate of rotation of the cutters 58.

The operation of the device above describedis as follows:

The basket 82 withits layer 28 of precoat is bolted in place as shown inFigure l and the casing maintained filled through the inlet 2 with theliquor to be filtered, at any desired pr'essure. As filtrationprogresses due to the difierential filtering pressure so imposed betweenthe two sides of the precoat 251i, filtrate passes through the precoatinto the chamber defined by the casing i and the basket i2 and isdischarged through the filtrate outlet 3. Simultanedusly a -film orlayer of solids is deposited on the outer or exposed surface of theprecoat. The rotation of the shaft 3l results in the rotaton of theblades l3 and in the downward movement of the baring 63 formedin theupper end of the frame 4| and carries 'at' its upper end a ring gear H,

. hollow shaft n so that'thecutters n continuously shave'oflnot'only thecake of solids deposited on the precoat 20 but alsothe outer surface ofthe precoat; soas'continuously to present to the liquor being a. freshfiltering surface If desired, the layer 20 of precoat material may bedeposited on the basket I2' by circulating through the filter a liquidin which is suspended the material from which the precoat is made.However it is believed that by having available a number of baskets onwhich a precoat has been previously deposited, a considerable saving oftime will be effected, for the time required to change the baskets isless than the time required for building up a layer of precoat by anindependent precoating operation.

Obviously a filter as above described may be -operated either as avacuum filter or as a pres sure filter, the only requirement being thata difi'erential pressure be imposed between the two sides of the filtermedium. v

I claim:

1. A filter comprising: a filter cell provided with a conicalfilteringsurface formed of a substantial layer of comminuted materialand designed to be subjected to a differential filtering pressure; alongitudinally movable rotary shaft coaxial with said filtering surfaceand provided with a cutter arranged to rotate therewith and describe aconical surface of revolution over said filtering surface; -alongitudinally immovable shaft coaxial and having threaded engagementwith said longitudinally movable shaft; a drive shaft adjacent andparallel to said longitudinally movable shaft; means for driving saidlongitudinally movable shaft so as to advance said cutter into saidfiltering surface from said drive shaft; a plurality of gears of varyingsizes driven by said drive shaft; a gear carried by said longitudinallyimmovable shaft; and means for selectively meshing said gear with anyone ofsaid Y plura1ity of gears.

2.A pressure precoat filter compris ing: a

totally enclosed liquid-tight casing; a filter cell eiecting relativerotatio'n between said shafts.

JAMES M. CHAIMERS.

